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i82014
Auditory and Non-Auditory Factors that potentially influence Virtual Acoustic Imagery
Durand R. Begault
NASA Ames Research Center
Moffett Field, CA
USA
Both auditory and non-auditory factors affect the ability for a sound designer to manipulate auditory localization, distance, and environmental context perception. The influence and possible detrimental effects of room acoustics, listening position, and spatial and temporal asynchronies are reviewed. Different approaches to spatial evaluation are reviewed in light of the demands of the application context.
i38442
Objective measures of spaciousness and envelopment
David Griesinger
Bedford, MA
USA
Research into concert hall acoustics has shown that acoustic preference is strongly influenced by spatial properties of the soundfield. Commonly discussed perceptions include Apparent Source Width (ASW), "Intimacy", and Listener Envelopment (LEV). Objective measures of these perceptions have proved difficult to construct, in part because the perceptions depend strongly on the source signal. Current measures for these properties have not always given consistent results, and are not in general applicable to sound systems in small rooms. This paper will discuss the strengths and weaknesses of conventional measures. It will present two new measures, the Diffuse Field Transfer function (DFT), and the Average Interaural Time Delay (AITD), that are useful at low frequencies in small rooms.
s55913
Effect of increasing system latency on localization of virtual sounds
Elizabeth M. Wenzel
Moffett Field, CA
USA
In a virtual acoustic environment, the total system latency (TSL) refers to the time elapsed from the transduction of an event or action, such as movement of the head, until the consequences of that action cause the equivalent change in the virtual sound source. This paper reports on the impact of increasing TSL on localization accuracy when head motion is enabled.
s70716
Spatial attribute identification and scaling by Repertory Grid Technique and other methods
1) Jan Berg, 2) Francis Rumsey
Luleå University of Technology
Sweden
2) Institute of Sound Recording
University of Surrey
UK
In the search for suitable ways to assess the spatial performance of sound reproducing systems, various research methods from the fields of psychology and the behavioural sciences may be considered. Selected approaches are reviewed, with particular emphasis on the Repertory Grid Technique (RGT). A pilot experiment relating to spatial parameters, inspired by RGT, is described.
s07527
The impact of decorrelated low-frequency reproduction on auditory spatial imagery: Are two subwoofers better than one?
William L. Martens
University of Aizu
Aizu-Wakamatsu, Fukushima
Japan
In contrast to sound reproduction systems using one subwoofer, the use of two subwoofers enables the presentation of decorrelated low-frequency signals that produce useful variation in auditory spatial imagery. Controlled listening experiments confirmed that this variation is lost when decorrelation is not reproduced at low-frequencies, and that this loss is particularly great for signals exhibiting negative values of cross correlation.
s58741
Measurement of the localization performance of virtual surround systems using synthetic test signals
Eric Benjamin, YiKuong Chen
San Francisco, CA
USA
Virtual Surround systems attempt to create acoustic images that appear to originate across the space subtended by the virtual speaker locations and the physical speakers. The performance of Virtual Surround systems can be subjectively judged by direct comparison to discrete multichannel reproduction systems. Such comparisons reveal differences in the perceived Virtual Surround and discrete multichannel sound field. Quantitatively evaluating and ranking the localization performance of these systems is difficult because of the large number of perceptual factors which are affected by Virtual Surround reproduction. Evaluation of the localization performance is facilitated by the use of synthetic test signals that are spectrally constrained to a narrow band of frequencies.
s68950
Acoustic Properties and Perceptive Implications of Stereophonic Phenomena
1) Jérôme Daniel, 1) Jean-Bernard Rault, 2) Jean-Dominique Polack
Cesson-Sévigné Cedex, France
2) CNRS-Laboratoire d'Acoustique Musicale
Université Paris, France
A method for acoustically and perceptively characterising stereophonic phenomena is applied using the velocity vector. The latter is first defined as a synthetic descriptor of local acoustic properties in any sound field, from which localisation cues can be objectively derived. When applied to sound imaging systems, usual laws and artefacts are interpreted, and compromises are highlighted depending on the loudspeaker geometry.
s03707
Product Design Considerations for Implementing 3D Audio Algorithms within Existing Multichannel Formats
Nicolas Sincaglia, Sylvain Rebaud
USA
This paper discusses the technical considerations of implementing 3D Audio speaker/headphone algorithms using the multichannel formats available today. Demand for virtual surround sound requires engineers to use multichannel standards in ways never intended by their designers. The consumer audio industry's high expectations and inexperience with virtual audio creates unique engineering issues of which potential solutions and trade-offs are discussed.
s48310
A Distributed System for the Creation and Delivery of Ambisonic Surround Sound Audio
Richard Foss, Adrian Smith
Rhodes University
South Africa
A system has been created for the production of ambisonic surround sound compositions using a client-server architecture. Those calculations requiring processing power and large amounts of disk storage and disk access are relegated to the server, while the client provides an intuitive user interface and limited processing. The server plays the role of a remote surround-sound processing engine, which can be utilized by clients. The system has been constructed and the feasibility of the approach evaluated via experimental data.
s40829
From Surround To True 3-D
Peter Lennox, Tony Myatt, John Vaughan
University of York
Heslington, York
UK
To progress from surround sound to true 3-D requires an updating of the psychoacoustical theories which underlie current technologies. This paper shows how J.J.Gibson's ecological approach to perception can be applied to audio perception and used to derive 3-D audio technologies based on intelligent pattern recognition and active hypothesis-testing. These technologies are suggested as methods which can be used to generate audio environments that are believable and can be explored.
s47438
Real-Time Virtual Acoustics for 5.1
Patrick Flanagan, Glenn Dickins, Leonard Layton
Sydney, NSW
Australia
A large body if knowledge exists for 3D acoustical simulation over speaker arrays. These techniques can be used for generating surround material for the 5.1 speaker format. Using such tools the mixing process is replaced by the concept of creating virtual acoustical simulations for which the 5.1 speaker array is the target reproduction array.
s92120
Software Toolbox for 3D sound using Loudspeakers
Jose Javier Lopez, Alberto Gonzalez
Universidad Politecnica de Valencia
Gandia
Spain
This paper describes a versatile software toolbox, which has been developed for researching, teaching and developing in the field of multichannel and 3-D sound signal processing. The software system runs on a PC using any compatible sound card and consists of 5 modules covering some of the main stages and aspects of 3-D sound reproduction using loudspeakers. Multichannel real-time filtering, MLS measurements, inverse filter computation, virtual source placement can be carried out with this tool.
s20051
Spatial Frequency Response Surfaces (SFRS's): An Alternative Visualization and Interpolation Technique for Head-Related Transfer Functions (HRTF's)
Corey I. Cheng, Gregory H. Wakefield
Department of Electrical Engineering and Computer Science
Ann Arbor, Michigan, U.S.A.
This paper introduces Spatial Frequency Response Surfaces (SFRS's), an alternative, spatial-domain visualization tool for head-related transfer functions (HRTF's). Qualitative analysis of SFRS's is easier than direct comparison of HRTF magnitude responses, and reveals many cross-subject similarities in HRTF data corresponding to well-known HRTF-related psychophysical phenomena. We present an SFRS-based HRTF interpolation algorithm, along with results of a psychophysical experiment comparing the perceptual quality of interpolated and non-interpolated HRTF's.
s82740
A Machine-Independent 3D Positional Sound Application Programmer Interface to Spatial Audio Engines
Warren Dale
Encinitas, CA
USA
The public Java 3D interface AudioDevice3D provids a mechanism for initialization and control of positional and directional sound sources on a wide array of spatial audio rendering engines. Details regarding the model and methods of this interface, examples of implemntations using particular audio engines, and sound of this interface's application are given in this paper.
s17623
Immersive 3-D Sound Reproduction in a Virtual Room
1) Tapio Lokki, 2) Lauri Savioja, 1) Jarmo Hiipakka
Telecommunication Software and Multimedia Laboratory
Espoo
Finland
2)
Helsinki University of Technology
Laboratory of Acoustics and Audio Signal Processing
Espoo
Finland
The 3-D audio reproduction in virtual rooms is discussed. The concept of virtual room is overviewed pointing out the use of sound in immersive virtual environments, and the acoustical issues of the virtual room are discussed. Different spatial sound reproduction techniques are overviewed. As a case study we report the spatial audio reproduction system currently under construction at Helsinki University of Technology.
s49525
Sound Moving Control for Home Theater Applications
1) Sergey Novikov, 2) Sergey Grigoriev, 3) Dmitry Elyashev
2) Russian Ac. Sci. State Oceanology Institute, Moscow, Russia
3) Film Director, Producer, Moscow, Russia
Fast algorithms for accurate sound localization in space are proposed. They are based on approximation of summary sound spectrum, obtained from 5 speakers, to one which must be percepted from virtual source placed at given point in space. The appropriate software allows to avoid using of an expensive hardware, the same accuracy being provided. The proposed virtual source simulation algorithm is based on the following assumptions: a) a considerably narrow frequency band can be locally represented by a single sine function; b) the third component (height) of the virtual sound source is defined by reflection and some other spectral features that are intrinsic to initial signal. Monte-Carlo method was used to get regularized solution. We developed compact software that allow to make complete calculations for the whole 40 sqr.m. grid with 12 cm. step in 0.2-1.5 min. on Pentium II, depending on accuracy. After these short preliminary calculations, any path or localization of sound can be defined in real play time on Pentium II, final construction taking 0.2-1 min. for 10 sec. of sounding. The input data for this software is a standard mono WAV-file with 44100 smpl/sec, and output are 5 WAV-files which could be played simultaneously on 5 speakers. For this purpose we used GINA sound card (ECHO Corp.). The proposed method was specially designed and applied for certain art projects (video and music), we assume to demonstrate the corresponding results.
s24928
Multichannel Electromechanical Film Panel Loudspeaker
Marko Antila, Hannu Nykänen, Kari Saarinen
Tampere
Finland
Flat panel Electromechanical Film (EMF) loudspeakers operate on electrostatic principle. In the EMF loudspeakers, the Electromechanical Film vibrates inside the porous plates in the electric field producing sound. The size of a loudspeaker panel is 500 mm x 600 mm. Nine panels are joined together to 3 x 3 configuration to form a large, flat surface. Each panel is driven with individual signal. The behaviour of the system is studied by modelling, measurements, and listening tests.
s60930
AML | Architecture and Music Laboratory
A museum
installation
1) Pierre Dutilleux, 2) Christian Müller-Tomfelde
Institute for Music and Acoustics
Karlsruhe
Germany
2) now at GMD-IPSI
Darmstadt
Germany
formerly at ZKM | Institure for Music and Acoustics
A museum-exhibit gives the visitors an opportunity to experience the relation between sounds and performance space. The impulse responses of real rooms have been measured and a simulator (Spatialisateur) has been programmed to imitate these spaces. Elementary volumes are imitated using simpler algorithms. A tracking system enhances the spatial illusion by compensating for the mouvements of the listener's head.
s91133
The computer synthesis and reproduction of 3D sound environments - research towards an implementation for blind students
1) Martyn Cooper, 1) Mark Pearson, 2) Helen Petrie
2) University of Hertfordshire, Hatfield, UK
This paper describes ongoing work towards the application of rich 3D sound environments within education. Prototype 3D sound environments have been constructed by synthesising Ambisonic B-Format signals using a proprietary DSP module and a PC. The paper describes these implementations and the results of detailed practical, technical and perceptual evaluations undertaken with both blind and sighted subjects.
s80055
Experiments on the synthesis of virtual acoustic sources in automotive interiors
Yuvi Kahana, Philip A. Nelson, Seongho Yoon
Southampton University
UK
This paper presents the theoretical background to various strategies for inverse filtering of room acoustic response. Results are also presented of objective and subjective experiments designed to evaluate the effectiveness of a signal processing system which produces virtual acoustic sources in automotive interiors. The emphasis in this work was on finding the scheme which creates the most robust solution with respect to localisation accuracy, as well as the size of the 'sweet-spot', in addition to the clarity and the minimal colouration of the reproduced signals. It is shown that by inverting only the first wavefront and reflections of the impulse responses in the car, captured in a free-field model (which includes the inner parts of the doors, the driver seat and the dummy-head) in an anechoic chamber, better performance is achieved compared with the other inversion strategies investigated.
s11717
Neural network approach to analyze spatial sound localization
Kalle Palomäki, Ville Pulkki, Matti Karjalainen
Laboratory of Acoustics and Audio Signal Processing
Espoo
Finland
Self-organizing maps (SOM) and multilayer perceptron (MLP) neural network approaches are applied to the evaluation of spatial discrimination of real and virtual sound sources. Neural networks are trained with localization cues computed using a binaural model. The ability of the models to simulate human perception of spatial sound is analyzed. Both SOM and MLP showed relatively good ability for generalization when tested with test data from real sources not included in the training data set. Both models were also capable of describing localization blur of virtual sources though still further analysis is needed to find out how well our models correspond to real human auditory localization. The motivation of this study has been to search for methods and techniques to evaluate the quality of spatial sound reproduction
i91359
Controversies and Mysteries in Spatial Hearing
Brian C. J. Moore
University of Cambridge
UK
This paper addresses three areas: (1) how good are human listeners at localizing sounds when multiple sound sources are present, and how is that ability affected by the number of sources?; (2) What role does spatial information play in the perception of auditory objects?; (3) Is the precedence (Haas) effect "hard-wired" in the brain, or does it depend on cognitive processing?
s89218
Localization, Coloration, and Enhancement of Amplitude-Panned Virtual Sources
Ville Pulkki, Matti Karjalainen, Vesa Välimäki
Laboratory of Acoustics and Audio Signal Processing
Espoo
Finland
The spread and coloration of pair-wise panned virtual sources are investigated in listening tests. The results are compared with results from corresponding simulations using a binaural auditory model. The results show that amplitude panned virtual sources produce highly conflicting cues at frequencies between 700 Hz and 2 kHz, and that they are localized according to different cues depending on signal attributes. A DSP-based method for enhancing the virtual source quality is proposed.
i32356
A comparative study of 3D audio encoding and rendering techniques
1) Jean-Marc Jot, 2) Veronique Larcher, 2)Jean-Marie Pernaux
Scotts Valley, CA, USA.
2) IRCAM,
Paris, France
This paper reviews and compares several techniques for multichannel sound panning over loudspeakers, as well as their application to computationally efficient 3-D sound spatialization over headphones. Ambisonic and pairwise amplitude (or intensity) panning approaches are reviewed within a general encoding/decoding framework. The performance of the different techniques is evaluated by use of objective criteria of auditory localization, and in terms of reconstruction of interaural time differences and HRTF spectral cues at the listener's ears. Improved approaches to efficient binaural synthesis are discussed, whereby interaural time differences are explicitly controlled. Specifically, the performance of the ``binaural B format" encoding/decoding scheme is evaluated, and practical applications of this technique are reviewed.
s73345
Spectral and Time-Domain Preprocessing and the Choice of Modeling Error Criteria for Binaural Digital Filters
1) Jyri Huopaniemi, 2) Julius O. Smith III
2) CCRMA, Stanford University, Stanford, CA, USA
In this paper, we discuss methods for preprocessing and digital filter design with application to 3-D sound. It is clear that binaural filter design can be optimized by taking into account such properties of human hearing as non-uniform frequency resolution and a logarithmic magnitude scale. We show that by choosing proper spectral and time-domain preprocessing techniques the choice of filter design method becomes a relatively trivial task. The validity of preprocessing methods is proved using a binaural auditory model. Filter design techniques based on optimizing the Hankel, Least squares and Chebyshev norms will be discussed.
s68608
Modeling the Contralateral HRTF
1) Carlos Avendano, 2) Richard O. Duda, 1) V. Ralph Algazi
University of California at Davis
Davis, CA
USA
San Jose State University
San Jose, CA
USA
We show how an effective model for the contralateral head-related transfer function (HRTF) can be obtained through a simple transformation of the ipsilateral HRTF. The appropriate interaural time difference is obtained from a spherical head model, and can be readily customized for each listener. The results produced are remarkably close to those produced by individually measured contralateral HRTF's.
s95934
Comparison of different interpolation methods for the interpolation of head-related transfer functions
1) Klaus Hartung, 1) Jonas Braasch, 2) Susanne J. Sterbing
Ruhr University, Bochum
Germany
2)
Dept. of Zoology and Neurobiology
Ruhr University, Bochum
Germany
Different methods for the interpolation of head-related transfer functions (HRTFs) were compared. Time domain representations (FIR coefficients) and frequency domain representations (discrete Fourier transform of the impulse response) of an HRTF catalogue were interpolated with the inverse-distance weighting method and the spherical spline method. The interpolated transfer functions were either compared with regard to numerical errors or to differences in perceived quality. In general the errors seem to be larger for time domain representations. Best results were achieved with spherical spline interpolation in the frequency domain.
s52654
Numerical modelling of the transfer functions of a dummy-head and of the external ear
1) Yuvi Kahana, 1) Philip A. Nelson, 1) Maurice Petyt, 2) Sunghoon Choi
Southampton University, UK
2) Samsung, SAIT, Supercomputing Applications Lab, Korea
Numerical modelling of the acoustical characteristics of exterior domains is a powerful tool which can be used for modelling HRTFs and sound fields produced by virtual acoustics systems. Two methods can be used: the Boundary Element Method (BEM) and the Infinite-Finite Element Method (IFEM). This paper presents the principles of using these methods by calculating the transfer functions of a sphere, an ellipsoid, a dummy-head (with and without pinnae), and a pinna of a dummy-head modelled on an infinite baffle. Simulations were performed on converted BEM and IFEM meshes with different mesh resolutions. These feasibility studies show that for models for which the geometry is captured very accurately (e.g. by means of a linear laser scanner/digitiser) it is practicable to simulate the response over the entire audible frequency range.
s33321
Measurement of cross-talk cancellation and equalization zones in 3-D sound reproduction under real listening conditions
1) Jose Javier Lopez, 1) Alberto Gonzalez, 2) Felipe Orduña-Bustamante
Universidad Politecnica de Valencia
Gandia, Spain
2) Centro de Instrumentos
Universidad Nacional Autonoma de Mexico
Mexico D.F., Mexico
This paper presents an experimental evaluation of the robustness of cross-talk cancelers in real listening conditions. Performance of the system with respect to channel separation and size of the equalisation zones has been analysed. A system for head-related cross-talk cancellation of two-channel audio signals was implemented in a slightly reverberant listening room. Measurements in and around the listening position were carried out in order to evaluate the performance of the system. In order to improve performance, other configurations were tried on.
s97524
Implementing Cross-talk Cancellation Networks using Warped FIR Filters
1) Ole Kirkeby, 1) Per Rubak, 1) Lars G. Johansen, 2) Philip A. Nelson
Aalborg, Denmark
2) Institute of Sound and Vibration Research, University of
Southampton,
Highfield, Southampton, UK
Conventional finite impulse response (FIR) filters are not ver efficient for providing the low- frequency boost required for efficient cross-talk cancellation over a wide frequency range. Warped FIR (WFIR) filters are better suited for the task since they have better resolution at low frequencies. An implementation of a cross-talk cancellation network for the stereo dipole demonstrates the advantage of using warped filters.
s06949
Optimization of virtual sound reproduced using two loudspeakers
1) Kevin C.K. Foo, 1) Malcolm O.J. Hawksford, 2) Michael P. Hollier
Department of Electronic Systems Engineering
University of Essex, Colchester, UK
2) BT Laboratories, Martlesham Heath, Ipswich, UK
An experiment on the subjective performance of virtual image accuracy is reported when a sound source is reproduced by a 2-loudspeaker array. Assessments are made for a range of loudspeaker subtended angle and loudspeaker distance to identify the optimum loudspeaker positions for a given image location, knowledge relevant to designing multi-loudspeaker arrays. Additionally, the effects on spatial sound reproduction due to different loudspeaker driver configurations and technologies are studied including near-field anomalies.
s22906
Immersive Spatial Audio for Telepresence Applications: System design and implementation
Andrew Rimell
Ipswich, Suffolk
UK
Immersive environments for teleconferencing, collaborative shared spaces and entertainment are set to become key elements of future communications systems. Spatial audio is an essential part of this emerging immersive environment technology. This paper describes a number of immersive environments developed at BT Laboratories covering the design and implementation of spatial audio for a range of systems from a single person SmartSpace chair using transaural processing to a multi-user VisionDome using a combination of ambisonics and non-linear panning. It was necessary to take existing spatial audio techniques and adapt them to suit our specific needs.
s82152
High Quality Multichannel Audio: Trends and Challenges
Marina Bosi
Los Angeles
USA
After the introduction of the CD format, new standards for consumer expectations have risen to demand audio quality that corresponds to the equivalent of signal to noise ratios and dynamic ranges of above 80 dB and signal spectral content of above 15 kHz. While the CD format specifies only two channels, multichannel audio is providing the end users with a more involving experience and it is becoming more and more appealing to music producers. Standardization bodies including SMPTE, EBU, ITU-R, ISO/IEC MPEG, DVD Forum have converged to the so called 5.1 multichannel format. The current development in DVD-Audio includes multichannel audio along with an increased audio sample resolution (24-bit) and sampling rates (88.2, 96, and 192 kHz). In spite a steady increase in storage media capacity and transmission bandwidth, high quality multichannel audio creates a challenge for traditional and new delivery media. In this paper, an overview of multichannel audio coding will be provided. The emerging DVD-Audio standard will be discussed. Applications and new directions in multichannel music will be examined.
s50601
Multi-Channel audio as an Immersive Entertainment experience
Frederick J. Ampel
Overland Park, KS
USA
As the technological capabilities for presentation and encoding/decoding of multi-channel audio signals/programs increase, a most of the concern is devoted to the technical aspects of the process. For any technology to be truly successful it must supply the user with an experience or capability unobtainable through any previous technology incarnation. This paper examines those issues.
s59711
Future Transmission and Rendering Formats for Multichannel Sound
1) Ulrich Horbach, 2) Marinus M. Boone
Regensdorf
Switzerland
2)
Delft University of Technology
Delft
The Netherlands
Current standard 5.1 and 7.1 surround sound multichannel formats are only partly capable of giving a true 3D sound experience. Even advanced schemes, such as Ambisonics or Virtual Surround Panning, rely on a more or less restricted listening area. The solutions are reviewed, their drawbacks explained and proposals for future directions are given, with special emphasis to flexibility in transmission and rendering. It turns out that wave field synthesis is most promising because of its flexibility and its volume solution for the listening space. A prototype of a compact sized, cascadable loudspeaker line array, suitable for wave field synthesis in studios and at home, will be described.
s16936
Optimal 3D Speaker Panning
Matthew Flax, Glenn Dickins, Adam McKeag, David McGrath
Sydney, NSW
Australia
A set of speakers in an arbitrary 3D array can be used to create virtual sound source images to a large audience. The problem of maximising directionality and minimising panning artefacts is described in a mathematical context. An algorithm is proposed to maximise the directionality across the listening region. This solution is analysed and compared to fixed order sound-field techniques. Additions to the algorithm are provided for reducing panning artefacts when animating sound sources. The proposed algorithms have been implemented and auditioned with favourable results.
s23204
Realtime Room Acoustics using Ambisonics
Jackson Pope, David Creasey, Alan Chalmers
Bristol
UK
Due to the complexity of environmental acoustics, Virtual Reality applications have to use a simplified model in order to achieve realtime processing of the sound information. This paper discusses a two stage technique for simulating room acoustics. In the first stage an accurate model of the room's impulse response is generated along with a graphical model of the environment. In the second, the user explores the environment in realtime.
s66819
3D-Sound Reproduction over an Extensive Listening Area: a Hybrid Method Derived from Holophony and Ambisonic
Rozenn Nicol, Marc Emerit
Lannion
France
Two methods of 3D-sound reproduction for videoconferencing are compared: Holophony and Ambisonic. Previous studies have shown that they are based on equivalent reconstruction process. First comparisons between their sound pick-up approach conclude that the Ambisonic spatial encoding is more efficient, though unfeasible. The present paper completes this analysis by examining the sound reproduction step. Finally a hybrid method is proposed.
s57035
Low-latency convolution for real-time applications
Christian Müller-Tomfelde
Darmstadt
Germany
formerly at ZKM | Center for Art and Media Technology Karlsruhe
Institute for Music and Acoustics
Karlsruhe
Germany
The real-time convolution of a sound signal with measured or computed room-impulse responses poses severe problems as regards computation load, system latency and memory requirements. Some key features of frequency-domain convolution allow to solve the dilemma between latency and computational complexity. Extrapolation from nowadays implementations on off-the-shelf computers allows to sketch future software solutions. In addition the properties in structure and dynamic of the room-impulse responses match ideal with those of the low-latency convolution algorithm for real-time spatial sound processing.
s03943
Creating Virtual Surround using Dipole and Monopole Pressure Fields
John Norris
Northridge, CA
USA
The objective of virtual 3D sound technology is to convey to the listener an accurate impression of an acoustic environment. This is accomplished by conveying a realistic directional impression of sounds. Most of the successful techniques for doing this are based on the head related transfer function (HRTF). In this paper we shall present a new method that creates the desired pressure field using dipole and monopole pressure fields. The object is to recreate locally the pressure field an actual sound source would produce, in a neighborhood of the listener's ears.
s27926
A real time algorithm for stereophonic multichannel localization of moving sound sources
Riccardo Dapelo, Simone Macelloni
This paper presents a real time stereophonic version of the model proposed by Moore(1983). The starting point is a concert situation for the electroacoustic music (with two or four channels); like this the concert hall can assume every shape and dimension, creating a virtual sound environment quite independent in shape and dimensions of the place where the music is played.
s16309
Applications of the CyberStage Spatial Sound Server
Gerhard Eckel
Sankt Augustin
Germany
We report about applications of spatial sound reproduction in immersive virtual environments realized with the CyberStage audio-visual display and the sound rendering system designed for it. A survey of the system's architecture and its hardware and software components is given. The different sound rendering methods employed are discussed in view of the wide range of applications realized with the system.
i15258
Methods for subjective evaluation of spatial characteristics of sound
Søren Bech
Struer,
Denmark
The total auditory impression of space is assumed to be a combination of a number of spatial characteristics or auditory attributes. The standard experimental procedures, developed for listening tests on loudspeakers cannot handle multidimensional attributes so it is necessary to develop new methods for such tests. The method introduced is termed Descriptive Analysis and was developed in the food industry to quantify food quality. The purpose of the method is to identify the auditory attributes of space, to devise methods for quantifying the magnitude of sensation for each attribute, and to establish the relation between the individual attributes and total auditory impression of space.
s15246
Investigation of listening conditions for multichannel sound systems
1) Eva Arato-Borsi, 2) Andor Fuerjes
Budapest, Hungary
2) Technical University of Budapest
Budapest, Hungary
In sound recording to test the different multichannel formats by listening tests calls for investigations of listening conditions. Well controlled sound is important and critical in reference listening rooms and recording rooms. In this paper the authors present some parameters for room acoustical evaluation of small rooms derived from the subjective and objective investigations. The results of the series of modelling are given.
s28948
Listening to Rooms and Objects
1) Richard McGrath, 1) Thomas Waldmann, 2) Mikael Fernstrom
University of Limerick, Ireland
2) Interaction Design Centre, University of Limerick,
Ireland
This paper describes a series of experiments with blind and sighted people in a "thinking aloud" study, attempting to identify our ability to describe the properties and their own location in two different rooms and the properties and locations of three different objects based on auditory cues generated by the participants themselves.
s72053
Design of rooms for multichannel audio monitoring
1) Ari Varla, 1) Aki Mäkivirta, 1) Ilpo Martikainen, 2) Martin Pilchner, 2) Richard Schoustal, 1) Christophe Anet
Iisalmi, Finland
2) Schoustal Inc.
Toronto, Ontario, Canada
There is a general understanding of how the monitoring speakers should be mounted and how the control room should be designed for best stereo performance. Similar practices are missing for multichannel reproduction. In this work the general requirements for multichannel monitoring conditions are analyzed and discussed. This includes the installation of speakers in the control room, treating of room surfaces for optimum imaging, direct vs. reverberant field spectrum in the listening position and directivity requirements for speakers. Measurements are performed in a 1:10 scale model and the results verified in real room.
s78357
Subjective comparison between Stereo Dipole and 3D Ambisonics surround systems for automotive applications
1) Angelo Farina, 2) Emanuele Ugolotti
Universita' di Parma
Italy
2) ASK Automotive Industries
Reggio Emilia
Italy
The paper describes the results of a subjective evaluation experiment: two methods for recording a three-dimensional sound field and for reproducing it through loudspeakers in a proper listening room are compared. The first method is the binaural method known as Stereo Dipole, based on digital filtering of binaural recordings or binaurally synthesized sound tracks: it allows for reproduction over a pair of closely-located loudspeakers. The second method is a software implementation of the well-known Ambisonics methodology, in which a B-format recording made with a Soundfield mic, or a synthesized B-format soundtrack, is reproduced over a 3D array of 8 loudspeakers. The subjective comparisons were made in a listening room fitted with 10 loudspeakers, and the listeners did not know at what of the two systems they were listening. Both reproduction systems were employed for blind evaluation of the sound field generated by audio systems of different cars.
s88447
Round robin subjective evaluation of VHT systems at the AES 16th International conference
Nick Zacharov, Jyri Huopaniemi, Matti Hämäläinen
Finland
Virtual home theatre systems are collected for a real time subjective test under controlled conditions during the AES 16th International conference. State of the art technology will be subjectively evaluated by delegates employing the GP2 subjective test system and compared against discrete 5-channel reproduction. Analyses of results are presented on the last day of the conference.
